8 of 40
Operating Manual:
SU780UE
10207.5
|
7.18.2016
2. Features of the SU780UE freezer
2.1 – Humm
™
Free-Piston Stirling Engine
The SU780UE Ultra-Low Temperature Freezer uses the
Stirling Ultracold Model M600 free-piston Stirling engine
to provide high efficiency, deep-temperature cooling.
No HCFC or CFC refrigerants are used in the M600 and
SU780UE. The M600 Stirling engine uses approximately 10 grams of helium gas as a
working fluid. About 90 grams of R-170 are used in the thermosiphon which removes
energy from the freezer.
2.2 – Cabinet Design Features
The cabinet utilizes vacuum-insulated panels with polyurethane foam support
providing an internal volume of cabinet approximately 780 liters. The environmen-
tally friendly blowing agent is Ecomate ®. A locking cam door latch ensures door
gasket compression when closed. Door sealing consists of three gaskets and is
factory replaceable. A door defrost minimizes water or ice deposition on the gasket
interface.
2.3 – Temperature Monitoring Features
Two resistance temperature detectors (RTDs) measure the internal cabinet tempera-
ture of the SU780UE. One provides input to the controller and the other provides
input for the Swift GUI display and for reporting and logging. Both RTDs may be
calibrated by the user through the Swift GUI. The Swift GUI provides a door open
timeout alarm and monitors the temperature reporting RTD for instances beyond
high and low limits that are set automatically or manually. Alarms are reported
through an audible alarm in the freezer enclosure and through a contact closure that
may be connected to an external alarm. The Swift GUI provides options to temporar-
ily suppress alarms and set a delay time before the alarm is reported via the contact
closure. A one-time temperature alarm suppression provided by the Swift software
allows for the initial cooling of the freezer after start-up.
